When it was all said and done at the 2018 US Open, Novak Djokovic tied Pete Sampras for third on the all-time list by hoisting his 14th Grand Slam singles trophy while Naomi Osaka celebrated her first Grand Slam title. They were far from the only notable stories at this tournament, however. Highlighted below are some of the US Open's pleasant surprises and disappointments, as well as young players to watch for in the future.
John Isner - After reaching the quarterfinals just once in his first 40 Grand Slam tournaments, Isner has done so in each of the past two, backing up his semifinal run at Wimbledon with a quarterfinal result in Flushing Meadows. Any conversation about Isner has to start with the serve, but the recent improvements to the rest of his game have been the key to his recent uptick in results. The top-ranked American still can't touch the Big 3, but he's firmly entrenched himself in the next tier.
Kei Nishikori - Injuries were to blame for Nishikori's decline since reaching the world No. 4 ranking in 2015, but the Japanese 28-year-old seems to have finally built his game all the way back up. Look for a healthy Nishikori to carry over the momentum from this semifinal run with a strong finish to the 2018 season and beyond.
Roger Federer - Fourth-round losses at the US Open are nothing to be ashamed of, but the way in which Federer allowed 55th-ranked John Millman to knock him out was shocking. Millman didn't need to do much besides keep the ball in play and let Federer implode, as the Australian Open champ donated 77 unforced errors, including 10 double faults. Rumors of Federer's impending demise have been overblown for years, but it's fair to question whether he can string together enough great performances to contend for big tournaments anymore while Rafael Nadal and Novak Djokovic are both healthy.
Alexander Zverev - If you only watch Grand Slams, you're probably wondering how Zverev is earning a top-10 seed, much less the No. 4 distinction. The 21-year-old German already has three times as many career Masters 1000 titles as three-time Grand Slam champion Stan Wawrinka (three to Wawrinka's one), but Zverev has failed to bring his best on the biggest stage. Whether he's folding under high expectations or doesn't trust his fitness in best-of-five tennis, it's unacceptable for Zverev to keep losing to players like Philipp Kohlschreiber and Ernests Gulbis when it matters most.
America's tennis development program - Young Americans have given us plenty to get excited about on the women's side, but we can't really say the same for the men. Of the 18 Americans in the draw on the men's side, only Isner and Taylor Fritz got as far as the third round, with the latter losing at that stage. America's Grand Slam drought stretches all the way back to Andy Roddick at the 2003 US Open, and it doesn't look like it's coming to an end any time soon.
Alex de Minaur - De Minaur has been shooting up the rankings of late, and the 19-year-old Australian showed why at this tournament. He dropped just three games to Taro Daniel in the first round, then dispatched of fellow youngster Frances Tiafoe in four convincing sets before falling to 2014 champion Marin Cilic in a five-set thriller. The decision to move from 32 seeded players to 16 starting at the 2019 Australian Open will reduce the likelihood of de Minaur earning easier draws in the immediate future, but he has the skills to make deep runs nonetheless.
Karen Khachanov - Khachanov gave Nadal all he could handle in the third round before the world No. 1 ultimately escaped with a 5-7, 7-5, 7-6 (7), 7-6 (3) victory. Considering Nadal won 6-1, 6-4, 7-6 (3) when the two met in the same round at last year's Wimbledon, it's clear Khachanov is making progress as far as his belief against the top guys goes. If the 6-foot-6, 22-year-old from Moscow stops running into Nadal early, he could soon start making some serious noise at the big tournaments.
Naomi Osaka - Serena's controversial run-in with the chair umpire took some luster off Osaka's breakthrough moment, but it's important to remember that Osaka was already up a set and in control of their championship match before Williams' coach made the hand motions that set off the tumultuous series of events to follow. The 20-year-old Osaka was incredible throughout this tournament, dropping just one set en route to the title. We've seen quite a few players on the women's side experience a temporary dip in performance after winning their first Grand Slam in the past few years, but those players were older than Osaka when they finally broke through and did so in less dominant fashion.
Anastasija Sevastova - Sevastova was overwhelmed by Serena in the semifinals, but just getting there was a tremendous accomplishment for the No. 19 seed. While she can't match the natural power of most opponents, Sevastova's mix of variety, speed and will to win have allowed her to achieve results that seemed unthinkable when injuries and illness led her to retire from tennis in 2013. Back and better than ever, the 28-year-old even avenged last year's heartbreaking quarterfinals loss to Sloane Stephens in the same round. Between Sevastova and basketball unicorn Kristaps Porzingis, New York has recently been treated to some amazing athletic performances by people born in the 70,000-person city of Liepaja, Latvia.
Top seeds - This tournament wasn't kind to highly-seeded women, with just one of the top five getting past the third round. Top-ranked Simona Halep came in nursing an Achilles injury and promptly became the first No. 1 seed ever to crash out in the first round of the US Open. Caroline Wozniacki came into this tournament struggling, and those struggles continued with a second-round loss to Lesia Tsurenko. Stephens actually made a respectable run to the quarterfinals, but her tournament ended with a 6-2, 6-3 loss to Sevastova, whom she defeated en route to the title in 2017. Angelique Kerber and Petra Kvitova both lost in the third round to players seeded outside the top 25. The highest-ranked women have had less of a stranglehold on the game than elite men in recent years, but this was a whole new level of disappointment for the top seeds.
Maria Sharapova - Sure, Sharapova knocked out 10th-seeded Jelena Ostapenko, or more accurately happened to be the player on the other side of the net while Ostapenko imploded with 41 unforced errors in 17 games. But the Russian star fell to 23-1 in night matches at Arthur Ashe Stadium with a straight sets loss to Carla Suarez Navarro in the Round of 16. Since serving a 15-month suspension for meldonium, Sharapova's reached the quarterfinals in just one of five Grand Slams. Her last 15 Grand Slams prior to the ban featured nine trips to the quarters or better and just one loss before the Round of 16. Whether purely mental or physical, Sharapova certainly seemed to get an edge from the prohibited substance that's no longer present in her game.
Coco Vandeweghe - Much was expected of Vandeweghe after she reached the semifinals at this tournament last season, but she followed up her breakout 2017 campaign with a nightmare 2018. Her first-round loss to Kirsten Flipkens dropped Vandeweghe to 1-4 in Grand Slam matches on the year. Vandeweghe salvaged her fortnight by winning the women's doubles title with partner Ashleigh Barty, but the American's singles game is in shambles.
Aryna Sabalenka - Sabalenka looks destined to crack the top five, maybe as soon as next season. The 20-year-old recently cracked the top 20, and she knocked off Kvitova in straight sets before losing 6-4 in the third to eventual champion Osaka. Sabalenka crushes the ball with her ground strokes, and she's getting better and better at controlling her power. Her run here should put the rest of the WTA on notice.
Marketa Vondrousova - Vondrousova tightened up and lost a very winnable fourth-round match to Tsurenko, but this tournament was still a rousing success for the Czech teenager. The lefty's best junior results came in doubles – she won the girls' doubles at both the Australian Open and French Open in 2015 – but she's quickly making a name for herself in singles as well.